Hi everyone.
Firstly, the reason there are no recommended items or masteries are because i have no clue how to do that stuff. This will be covered in writing though. If someone could tell me how i will update this guide so the format is easier to understand.

I usually take 9 lv3 marks of health, for early health, so you can team fight early. I take 9 lv3 seals of armour, and 9 lv3 seals of magic resist. All of this means you can be very tanky early on, so you gank more quickly, so your lanes will be won. Then take a lv3 quintessence of cdr, a lv3 quintessence of movement speed, and a lv3 quintessence of attack speed, so you move faster, and stack your W, your major damage ability, more quickly.

As for masteries, take 4/26/0. Take 4 points in fury to get your W quicker. In defence, take 2 points in swiftness, so you can initiate, 2 points in recovery, so you get regen other than your passive (don't try to proc for health, just back). Take 2 points in block, because those early banks botlane might leave you with 8 health you wouldn't have otherwise (this happens at least once a game for me). Take 3 points in veterans scar, for early tankyness, because banking early will always help you win, a point in unyielding, for the same reason as block. Take a point in tenacious, because you need to get in, initiate, then get out alive if things go wrong, and you can't do that when you are stunned. take a point in juggernaught, because late game you can get another 150 health out of this, which is like another basic attack from their ADC. Take 3 points in hardiness and resistance, for more damage reduction. Perseverance, because you need your passive for ganks and team fights. Adaptive armour, so if they have 3 APCs, the ADC won't kill you so easily. Reinforced armour
so ADC's don't crit you to death, which can kill you without proccing your passivem which is annoying. Take evasive, just because amumu or malzahar can completely destroy you with AoE max health damage. Lastly, take Opression, so you can survive things like Malzahar ults, or as he arrows, then finally, second wind, so your passive heals you even more.

When starting, take Hunter's Machete and 2 health potions. Immediately rush Ranger's Trailblazer with Cinderhulk, then get Boots of Swiftness. Then get Sterak's Gage for tanginess and damage. Take Warmog's so your passive is only proceed in fights. Then take Guardian Angel if you are losing or Titanic Hydra if you are winning. No matter what you build first, build the other one after.

Also, before building Warmog's take alacrity on your boots

Lv1-W
Lv2-E
Lv3-Q
Lv4-W
Lv5-E
Lv6_R
Lv7-W
Lv8-W
Lv9-W
Lv10-E
Lv11-R
Lv12-E
Lv13-E
Lv14-Q
Lv15-Q
Lv16-R
Lv17-Q
Lv18-Q

Take smite and flash unless your top lamer doesn't have teleport, in which case take smite and teleport.

So.
Your in the rift.
Gank whenever you are asked.
You will get kills at least half the time, and the other half they will waste use their flash, even if its to kill you after you mess up, as a rule.
The exception to this is, never gank before lv3.
Do drake at level 5 or 6, depending on if your botlane is winning or losing. If they are losing, gank at lv5, then farm and try again at level 6.
Then wait for opportunity, seizing them to steal as often as you can, because you should be able to team fight be this point.
When team fighting, activate Q, and run at their most fed carry. E when you get close. Then ult, and W until you can activate it, and in my experience, this will have killed ANY squishy carry. Don't run in without your team though. Wait for them to be behind you.
Chase kills all you want as long as your team is with you (i mean your whole team) If not, wait, ward, look for enemies, then chase. You might have lost out on a kill, but its better than being trapped and killed by the whole enemy team. As for baron, wait for your team to suggest it, and do what the most fed person says, so if they say don't, then don't. You can't baron with underfed team mates.

Apply same rules, but add extra caution, and don't chase kills, unless you are in a warded area. Ward whenever you can. but you don't need sighstone, but you should NEVER have your trinket not on cool down.

Pros:
Tanky
Does surprising amounts of damage
Lots of team fight potential: AoE cc and damage, carry killing potential
Passive saves you half the time, so very forgiving

Cons:
Honestly, the only con i can think of, is that he has no harass.

So, when jungling, start at Krugs. Then go to raptors then wolves. Then bank, and back. You might not have enough health for some reason or another, but don't bank if you are below half health. Offer team red and blues, but if no one replies take them. Counter jungling really depends or whether you are behind. If you have levels on their jungle, go nuts. If not, be careful, and stick to your jungle. Gank whenever you are asked, so long as you are above 40% health, and if not, back then gank. Don't bank before level 3.

Basically, initiate when your team is behind you, block skill shots for your squishy carries, and if its you or a team mate, see who is more fed, then sacrifice the less fed one. Always help low health people, unless you are low yourself

Unique skills:
Volibear does not have anything unique, but he does have very powerful skills, on account of they often combine 2 things
Q: Singed E + Righteous GLory.
W: Like Xin's Q and W put together, but instead of health and knock up, tons of damage to low health enemies.
E: Fiddles Q + Part of Lulu's ult
R: Zap everything: Too many examples to write down

Now, i think i need to rant here, before anything else
Jungles, DONT steal laners minions.
But for some reason, lanes kill jungle monsters.
Blue and reds are fine, but the amount of time people steal raptors for no reasonm really irritates me, and all my jungle main friends

Thank you all for reading, good luck, and please leave constructive criticism, and tell me how to insert rune, masteries, items, and all the other stuff better guides have, so i can improve